Concreting of walls and columns.-The concreting of the walls and columns for the shed of Pier No. 7 was 13 per cent complete at the end of the fiscal year 1915-16, by which time 308 cubic yards of concrete had been placed. During July, August, and the first half of September 2,039 cubic yards of concrete were poured, making a total of 2,347 cubic yards used. This work was completed on September 16, 1916, and the cost per cubic yard, including forms and reinforcement, was $22.88, or a total cost of $53,700.66. The method of construction is illustrated by Plate No. 19.

Paving. At the close of the fiscal year 1915-16, 279.000 paving brick had been laid on the floor of Pier No. 7, making this class of work 20 per cent complete. All paving work was completed by September 30, 1916, by which date a total of 1,381,000 bricks had been laid.

The paving bricks were furnished by the Murphysboro Paving Brick Company, of Murphysboro, Ill., at a unit price of $38.84 per thousand delivered at Cristobal. The total cost of the pavement in place was $68,011.16.

Pier No. 7 was first used for commercial purposes on September 20, 1916, when the steamship Ucayali was berthed and unloaded.

The completed pier is illustrated by Plate No. 20, on which will be noted the incomplete cylinders in the foreground upon which the port captain's launch house is to be built.

FILL AND TRACK YARD IN REAR OF THE CRISTOBAL FIRE STATION.

The work of laying the tracks on the new fill in the rear of the Cristobal fire station was started on June 28, 1916, and completed on March 24, 1917, after a considerable delay due to the slow delivery of ties and other track material.

The new track yard contains a total length of 14,185 lineal feet of track, and has a capacity of approximately 122 cars.

A total of 7,400 cubic yards of armor rock were used for armoring the new fill, of which 4,080 cubic yards were supplied from Sosa Hill, the remaining 3,320 cubic yards being recovered from the armor rock on the mole where the new fill joins the mole.

The armoring of the new fill was started in December, 1916, and completed on March 11, 1917.

EXTENSION OF THE CRISTOBAL MOLE.

The preliminary borings for the extension of the Cristobal mole which were started on February 9, 1916, and were 64 per cent complete at the end of the fiscal year 1915-16, were finally completed in September, 1916, a total of 22 holes having been drilled, consisting of 2,059 lineal feet of wash drilling and 176 lineal feet of diamond. drilling.

On June 10, 1916, work was started on a trestle to be used for dumping soft rock for an extension to the Cristobal mole. By June 30, 1916, 547 lineal feet of trestle had been driven, and on August 16 this work was temporarily stopped with a total of 742 lineal feet of trestle in place. During the first half of February, 1917, a further extension of 68 feet was made, giving a final total of 810 lineal feet. driven. The trestle work was started from the end of the mole as it was at the beginning of the fiscal year.

After completing the 742 lineal feet mentioned above, work was started on August 26, 1916, in the dumping of 119,414 cubic yards of soft rock from the Mount Hope borrow pit, to construct an extension to the mole. This work was completed in February, 1917. In addition to the 119,414 cubic yards of soft rock, 26,038 cubic yards of hard rock from Sosa Hill were placed along the north side of the mole extension as armoring. This work was started in January, 1917, and completed on March 17, 1917. The total cost of the fill was approximately $93,633.67.

APPROACH FILL FOR PIER No. 6 AND FILL FOR TRACK YARD.

The construction of the approach fill and fill for track yard for Pier No. 6 was started on June 12, 1916, and by the close of the fiscal year 1915-16 22,215 cubic yards of soft rock from the Mount Hope borrow pit had been dumped, and by December 31 of the fiscal year 1916-17 the work was completed with a total quantity of 129,448 cubic yards in place. The total cost of the fill in place was approximately $45,327.42, or $0.35 per yard. No armor rock was used in connection with this fill.

BOAT LANDING AND LAUNCH HOUSE BETWEEN PIERS NOS. 7 and 8.

The driving of 1,058 lineal feet of 3-foot diameter steel cylinders and 1,049 lineal feet of 4-foot diameter cylinders was started on September 15, 1916, and completed on March 18, 1917, after several months' delay due to the late delivery of a part of the required amount of 3-foot diameter cylinders from the United States. All the required. amount of 4-foot diameter cylinder material was secured secondhand on the Isthmus. The material for the 3-foot diameter cylinders, however, was supplied by the Riter Conley Company of Pittsburgh, Pa., at a contract price of $0.0414 per pound delivered flat.

The excavation of the cylinders was started on September 27, 1916, and completed March 24, 1917, a total of 536 cubic yards having been removed.

The concreting of the cylinders was started in October, 1916, and completed on May 27, 1917, a total of 754 cubic yards having been poured.

The cost of the steel cylinders in place was $11,746.64.

The cost of the excavation amounted to $2,922.63, or approximately $5.45 per cubic yard.

The cost per cubic yard of concrete in the cylinders was $6.55, or a total of $4,935.58, including all reinforcing.

The cost of the substructure complete, including surveys, preparation of site, designing and preliminary work, was $23,270.83.

All work on the substructure of the boat landing and launch house was completed with the completion of the concreting of the cylinders on May 27, 1917. It has not been possible to do any further construction work on the boat landing, due to the fact that no floor steel has yet been received. The contract for this steel was awarded the J. B. Kendall Company, of Washington, D. C., who agreed to complete the shipments from their mill on or before April 1, 1917, and to deliver the material on the Isthmus at a unit price of $0.0491 per

pound, or a total of approximately $14,684.34, the estimated weight being 299,068 pounds.

The shed steel for the boat landing and launch house was furnished by the Belmont Iron Works, of Philadelphia, Pa. The total weight of 213,685 pounds was delivered on the Isthmus during April and May. This material was supplied at a contract price of $0.06 per pound, or a total price of $12,821.10.

CONCRETE BLOCKS FOR THE EAST BREAKWATER.

During August, September, and October of the fiscal year ending June 30, 1917, 2,203 concrete blocks were shipped to the east breakwater making a total of 4,000 blocks poured and delivered by this division. These blocks measured 4 feet 3 inches on a side and contained a total of 11,200 cubic yards of concrete. No reinforcing was used. The total cost of the blocks manufactured at site and loaded on cars ready for shipment to Coco Solo was $41,653.56, corresponding to $3.71 per cubic yard, or $10.41 per block.

IMPROVEMENTS IN ROADWAYS AND NEW CUSTOM LINE FENCE.

On February 14, 1917, a work request was approved covering the expenditure of $17,020 for new road work for the Cristobal docks. Work was started shortly afterwards and completed in April on a new 30-foot road for an entrance to the docks. The surfaces in front of Pier No. 8 and Dock No. 9 which were formerly grass plots were also concreted over, increasing to a great degree the traffic facilities of the docks. Likewise the macadam road alongside the electric charging station was concreted as were the areas in front of and alongside the new local freight house. In addition to the above a concrete road was constructed alongside the new track yard and parallel to the custom line fence for a distance of 286 feet from the new road entering the docks.

A new fence has recently been erected as a custom line fence for the docks. This fence was supplied by the Stewart Iron Works Co., of Cincinnati, Ohio, at a unit price of $2.85 per linear foot, or $2,580 for the 1,000 feet ordered. This fence was erected by this division, while the road work outlined above was performed by the municipal engineering division in accordance with plans prepared in the office of the engineer of docks.

PIER NO. 6.

After a careful consideration of the best site for the construction of a new pier, on July 21, 1916, Authority for expenditure No. 920 was approved covering an expenditure of $1,500,000 for the construction of Pier No. 6. The estimate upon which this Authority for expenditure was based was made in the office of the engineer of docks in August, 1915, and due to the short notice at which this estimate was required, it was assumed that the depth to rock and the material encountered would be the same as those for Pier No. 7. The borings, however, which were taken subsequent to the approval of Authority for expenditure No. 920 indicate that the total length of cylinders on Pier No. 6 will be 12 per cent greater than the total length of cylinders on Pier No. 7.

Dredging on site of Pier No. 6.-During the months of August and September, 1916, the dredging division performed 243,198 cubic yards of wet excavation on the site of Pier No. 6 which, at a unit cost of $0.0628 per cubic yard, amounted to a total cost of $15,273.89.

Final borings.-The final borings on the site of Pier No. 6 were started in September, 1916, and completed on January 24, 1917. A total of 93 holes were driven consisting of 6,602 linear feet of wash drilling. The total cost of the borings was $2,496.69, or $0.378 per linear foot.

Trestle and false work.-On September 2, 1916, a contract was awarded the J. G. Rainwater Lumber Co., of New Orleans, La., to furnish and deliver at Cristobal, Canal Zone, 545 yellow pine untreated 75-foot piles at $0.46 per linear foot, or at a total cost of $18,802.50. The delivery of the piling was started in November, 1916, and completed in January, 1917. The driving of the trestle was started in October, 1916, with piling secured on the Isthmus, and was completed with the piling furnished from the United States, in February, 1917. A total of 1,135 linear feet of trestle and false work were driven at a unit cost of $36.23 per linear foot, and the total cost of the trestle and false work together with the necessary power and water lines and temporary tracks was $47,489.17, or $41.84 per linear foot of trestle.

Cylinders.-All caisson material was furnished from the United States with the exception of approximately 3,655 lineal feet of secondhand material secured on the Isthmus. The contract for 12,625 lineal feet, or 5,403,614 pounds, of steel caisson material was awarded the Riter Conley Co. on September 1, 1916, at a unit price of $0.0337 per pound, or a total price of $192,909, the material to be delivered flat.

The delivery of the caisson material was started in December, 1916, and completed in April, 1917.

The rolling and assembling of the caisson material was performed by the mechanical division at the Cristobal shops at a unit cost of $4.206 per lineal foot, amounting to a total cost of $53,105.31.

The driving of the cylinders was started on November 29, 1916, and at the end of the fiscal year 1916-17 was 65 per cent complete with a total of 15,855 lineal feet in place.

The excavation of the cylinders started about December 15, 1916, and at the close of the fiscal year was 63 per cent complete, 10,503 cubic yards of material having been removed.

The concreting of the cylinders was started on January 25, 1917, and at the close of the fiscal year was 44 per cent complete, a total of 10,987 cubic yards having been poured.

Due to the high cost of piling it was found that in case the same construction of four trestles as was used for Pier No. 7 should also be used for Pier No. 6 the increased cost of the foundation work for Pier No. 6 would be approximately $100,000. This increase in cost is believed to be eliminated by the use of floating equipment in connection with but one trestle instead of four as was the case with Pier No. 7. Accordingly derrick barges Nos. 156, 157, and 161 were transferred to this division to be used in setting, driving, excavating, and concreting the cylinders. The concrete-mixing plant is mounted on derrick barge No. 161, while derrick barges Nos. 156 and 157

perform the other work mentioned above in connection with other equipment mounted on pontoons or running on the trestle.

During the first half of the fiscal year plans and specifications were prepared for the structural steel and miscellaneous ironwork for the floor system of Pier No. 6. The total estimated weight of 11,059,050 pounds included the predominating weight of 10,444,000 pounds of structural work. Bids were advertised for during January and February of 1917 and opened on February 12, 1917. The lowest bidder proved to be the United States Steel Products Co., whose bid A amounted to a total of $574,886.48 for the material delivered in Cristobal and whose bid B amounted to $639,218.48 for the material delivered and erected. Under bid A (i. e., not including the erection) the unit price for the structural steel was $0.052 per pound and under bid B the unit price was $0.056 per pound.

As the cost of the steel in place on Pier No. 7 was only $0.0227 per pound as compared to the above-mentioned bid of $0.058 per pound for Pier No. 6, an increase in cost of the floor of Pier No. 6 over that of Pier No. 7 amounting to $368,000 would result if the same construction were to be used as was used on Pier No. 7. Investigation showed, however, that a considerable reduction of this increase in price could be effected by the elimination of the structural steel floor system and the use of reinforced concrete. It is believed that the estimated total of 25,000 cubic yards of reinforced concrete required by the use of reinforced concrete construction instead of structural steel can be put in place for $17.50 per cubic yard, or a total of $436,000, which together with $89,000 worth of steel struts already ordered would make a total cost of $525,000. The cost of the floor system on Pier No. 7 was $413,000, so that an estimated increase in the cost of floor of Pier No. 6 of $112,000 will result, instead of $365,000, which would have been the case if the same construction were to be used as was used on Pier No. 7.

The redesign of the floor for Pier No. 6 has necessitated corresponding changes in the design of the shed, which it was originally intended to construct as nearly as practical identical to the shed of Pier No. 7.

Effective December 1, 1916, this division was transferred by Circular No. 660-31 from the Panama Railroad Co. to The Panama Canal, department of operation and maintenance.

It is expected to complete all work on the cylinders of Pier No. 6 not later than November 15, 1917, and to complete the work on the concrete floor by May 1, 1918, at which date the paving of the floor may be started. Provided no delay may be encountered in securing the shed steel, all deliveries should be completed by August 1, 1918, and the erection by November, 1918. It is believed that all work on the pier, including the concreting of the walls and the erection of the doors, will be completed on or before December 31, 1918.

PACIFIC TERMINALS.

A. R. Brown, Assistant Engineer.

DRY DOCK No. 1.

Miscellaneous work was done, consisting of completing installation of pipe lines and drains around dock coping, and manholes therefor;